Circuit breaker



March 27, 1934. F, J. HARDMAN 1,952,129

CIRCUIT BREAKER Filed D80. 26, 1929 f J 383% ffgugae/u,

Patented Mar. 1934 CIRCUIT BREAKER Frederick J. Hardman, Dayton, Ohio,assignor Delco Products Corporation, Dayton, Ohio, a corporation ofDelaware Application December 26, 1929, Serial No. 416,334

12 Claims.

This invention relates to improvements in thermostatically controlledswitches.

It is one of the objects of the present inven-;

tion to provide a temperature responsive switch having a quick make andbreak action and which has greater sensitivity than found heretofore inswitches of this type. This object is accomplished by providing a toggledevice comprising pivotally connected elements resiliently urged awayfrom each other 1 whereby the toggle tend to break, with respect to aline connecting the remote ends of the elements, in either directiondepending upon the location of their pivotal connection with respect tosaid line, said toggle device cooperating with thermostaticmembersoperable cumulatively to move said elements in oppositedirections respectively with respect to their pivotal connection and aswitch member which is actuated in response to the breaking of thetoggle.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawing:

Fig. 1 is an inverted plan view of the thermostatic switch with thecover plate removed.

Fig. 2 is a sectional view taken along the line 2--2 of Fig. 1, and.shows the contacts in engagement.

Fig. 6 is an enlarged detail view of the bracket structure as related tothe thermostatic element and pivoted member, this viewis taken alongline 66 of Fig. 1. v,

Fig. '7 is an enlarged view of the insulating connection between thecontacts provided for automatic resisting of the switch.

Referring to the drawing, the device is shown comprising a housing 20,preferably made up of any suitable insulating material. This housing maybe made up of metal which would require the insulation-of substantiallyall of the interior elements. However, by constructing the housing of amolded condensation product such as bakelite or the like, complexinsulation of the various movableparts within the switch is practicallyeliminated. a

The housing contains a thermostatic element 21 secured to the housing bya terminal screw 22 and a rivet 23. The one end of the thermostaticelement 21 carries a contact 24. This endof the thermostatic elementnormally rests against a stop screw 25 carried by the housing 20, thisscrew being adjustable so that this movable end of the thermostaticelement 21 may be maintained in a proper position by the adjustment ofthe screw 25. The other end of the thermostatic element 21 has ahook-shaped end as at 26.- I

p A. bracket 27 is secured in'the housing 20 by rivets 28, this bracket27 having an aperture 29 for receiving the plate 30. A tongue 31 ispressed or punched from the plate 30, said tongue engaging the'bracket2'7 and acting as a fulcrum for pivotally supporting the plate 30 uponsaid bracket 27. To maintain the tongue 31 in engagement with bracket27, a resilient element or spring 32 is interposed between the end ofthe hooked portion 26 of the thermostat 21 and the one end of the plate30. The spring is insulatingly supported upon the end of thethermostatic portion 26 by an insulating collar 32a, the opposite end ofthe spring being secured to the end of plate30 in any suitable manner. Acontact 33 is carried at one end of the plate 30, said contact beingadapted to engage the contact 24 supported at the end of thethermostatic element 21. As shown in Fig. 2, spring 32 is so positionedrelative to one end of 'the plate 30 and the thermostatic portion 26that'it exerts a force upon the end of the plate 30, urging the saidplate 30 in a counter-clockwise irection about its fulcrum tongue 31 sothat contact 33 is urged into engagement with the contact 24 on thethermostatic element 21. As shown in Fig. 3v the plate 30 is moved intoa position in which spring 32' is exerting pressure upon the end ofplate 30v to move the contact 33 out of engagement with the associatedcontact 24;

Plate 30 carries a terminal 35 to which one end of a wire 36 isconnected. The other end of this wire is electrically connected to oneend of the heater coil 37, the opposite end of said heater coil beingconnected to the screw 40 which is electricaliy'connected with screw 41forming a terminal for one end of the main wire leading to the switch.The heater wire 37 is wound about heat resisting and insulating material38 such as mica or the like, said material being supported uponstandards 39 provided in the housing 20.

As has been mentioned heretofore, the other ter- 'cuit through theswitch, the'resetting button 42,

preferably of insulating material and carried by the plate 30, ispressed so that the contact 33 engages with contact 24 supported bythermostatic element 21 which normally lies in the position as shown inFig. 2. As soon as the plate is moved into the position as shown in Fig.2, the spring 32 will be moved into the position in which it will exertpressure to move the plate 30 in a counter-clockwise direction about itsfulcrum tongue 31, thereby urging contact 33 into engagement withcontact 24. Current now flows from the main wire into the terminals 41and and thence through the heater coil 3'7, wire 36 to the terminal 35,plate 30 and thence across contacts 33 and 24, through the thermostaticelement 21, terminal screw 22 to the other side of the line. Excessivecurrent flowing through the heater coil 37 will eventually createsuflicient heat within the static element 21 moves so that its contact24 is urged against the contact 33 and thus said contact is moved in thesame direction against the effect of the spring 32 upon the plate 30.Movement of the contact 33 by the contact 24 away from the stop screw 25moves the plate 30 in a clockwise direction and thus the end thereof,engaged by the spring 32 will be moved toward alignment with the end 26of the thermostatic element 21 which also engages the spring. The heatwithin the housing 20 also causes the hookshaped end of the thermostaticelement 21 to flex, resulting in movement of the end portion 26 whichengages the spring supporting insulating washer 32a, in a directionopposite the movement of the end of the spring engaged by the plate 30,so that as the contact carrying plate 30 is moved clockwise by thecontact 24, the ends of the spring 32 are moved counter-clockwise,resulting in an alignment of the end 26 of the thermostatic element, theend of the plate 30 engaging with the spring, and the fulcrum tongue 31of said plate. As soon as the plate 30-is moved slightly beyond thisalignment, spring 31 will suddenly flip the plate 30 clockwise so thatcontact 33 is suddenly moved out of engagement with the contact 24, thecontacts 24 and 33 and their supporting members 21 and 30 respectivelyassuming the position as shown in Fig. 3. The circuit having beenbroken. the heat within the housing 20 will be dissipated, therebypermitting the thermostatic element 21 gradually to return to theposition as shown in the Fig. 2, after which plate 30 may again beoperated by the member 42 to close the circuit through contacts 24 and33.

In order to make the device self-setting. the operating member 42 mayhave an insulating stem 43 extending therefrom, through an opening 44 inthe thermostatic element 21, this portion 43 of the operating portionhaving an enlarged head 45 engaging the side of the thermostatic element21 opposite the plate 30. With this type of operating member 42 theplate 30 will be drawn toward the position as shown in Fig. 2 by thereturn movement of the thermostatic element 21 in response to loweringtemperatures so that, before said thermostatic element 21 reaches theposition asshown in Fig. 2, it will have moved the plate 30 into aposition in which spring 32 may suddenly flip said plate 30counterclockwise to cause its contact 33 to again engage the contact 24,said spring thus holding the plate 30 in position as shown in Fig. 2until suiiicient heat has been provided within the housing 20 to againfiex the thermostatic element 21, to move against the contact 33.

In the present invention applicant has provided a thermostatic switchincluding two movable contacts, one of which is movable by thethermostatic element, the other being mounted upon a pivoted arm andbeing movable through a certain range by the cooperating contact which,as has been mentioned, is carried on a thermostatic element.

One advantage of the present device is that while the thermostat isoperating to approach the instant in which circuit interruption isobtained, one contact, carried by the thermostatic element, is movingagainst the other contact whose movement is resisted by a spring so thatgood contact pressure is maintained until the instant the springsuddenly flips the contact carried on the arm out of engagement with thecontact carried on the thermostatic element. At no time is the contactpressure between said contacts reduced sufllciently to cause arcing, forboth contacts are being urged in opposite directions, one against theother, the force exerted by the thermostatic element overcoming that ofthe spring which urges its contact against the thermostatically operatedcontact. The contact supporting elements are so arranged that duringtheir operation, a slight rubbing movement between the contacts obtains,thereby tending to eliminate any pitting between the contacts caused byany arcing which might occur upon the sudden disengagement of saidcontacts.

Another feature of the device is that the spring is interposed betweentwo movable elements which at all times move in opposite directions,thereby tending to more sudden disengagement of the contacts and therebysubstantially reducing the possibility of arcing.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. A thermo switch comprising, in combination, a thermostatic striparranged to flex in response to temperature changes so as to occupy agiven position at ordinary temperatures and to move away from saidposition upon an increase in temperature; a contact carried at one endof said strip; a pivoted member; a contact carried at one end of saidpivoted member and adapted to engage the contact on the strip; andelastic means supported between the ends of said thermostatic strip andpivoted member opposite their contacts for urging the pivoted memberinto either its contact making or breaking position.

2. A thermo switch comprising, in combination, a thermostatic striparranged to flex in response to temperature changes; a contact carriedby said strip; a movable plate; a contact carried by said plate andadapted to engage the aforementioned contact; and a spring interposedbetween the thermostatic strip and plate, yieldably urging the contacton the plate into engagement with the contact on the strip while theformer isibeing moved by the latter and until a proper position isattained at which said spring is adapted quickly to move the plate todisengage its contact from the contact on the strip.

3. A thermo switch comprising, in combination, a housing, a thermostaticstrip insulatingly supported in said housing; a contact carried at oneend of said strip; a bracket insulatingly supported in the housing; anarm pivotally supported on the bracket; a contact carried at one end ofthe arm and adapted to engage the contact on the thermostatic strip; anda spring interposed between the other ends of the thermostatic strip andpivoted arm, said spring normally urging the arm to hold its contact inengagement with the coopcrating contact, said spring, however, beingshiftable by the operation of the arm by the thermostatic strip quicklyto move said arm into contact engaging position when the said arm hasbeen moved in a proper position by said strip.

4. A thermo switch comprising, in combination, a housing made ofinsulating material, a thermostatic strip supported within said housing;a contact carried at one end of the thermostatic strip; an arm pivotallysupported -within said housing; a contact secured at one end of said armand adapted to engage the aforementioned contact and a coil springinsulatingly supported between the other ends of the thermostatic stripand arm, said spring normally exerting pressure upon the arm to maintainits contact in engagement with the contact on the thermostatic switch,said spring, however, being shifted by the movement of the one end ofthe thermostatic device and the movement of the arm by the opposite endof the thermostatic device whereby said spring is adapted quickly tothrow the arm into contact disengaging position when a proper positionis attained.

5. A thermo switch comprising, in combination, a toggle devicecomprising pivotally connected elements, said device comprising anormally compressed helical spring and a lever pivoted intermediate itsends, a switch contact carried by the lever arm remote from the spring,a second contact engageable with the firstcontact, and a bimetallicthermostat fixed intermediate its ends so as to provide two thermostatmembers one of said members extending directly from the fixed pointtoward the first contact and carrying the second contact and the othermember having a portion extending also toward the switch contacts andconnected with one end of said spring, said thermostat members bendingin the same direction in response to temperature changes whereby theyare operable cumulatively to move the toggle elements in'oppositedirections, respectively, with respect to their pivotal connection.

6. A thermo switch, comprising in combination, a toggle device includingcooperating members, one of said members being pivotally mounted, meansresiliently forcing saidmembers away from each other on one side of thepivotal mounting, a contact secured to the pivotally mounted member onthe other side of the pivotal mounting, a cooperating contact adapted toengage the other contact, and thermostatic means for changing thedirection of the force of the resilient forcing means so that after apredetermined change of direction of the force said contacts disengageadapted to be engaged and one of which contacts is carried by one end ofthe extending arm, and thermostatic means for moving said arm andresilient means in opposite directions, respectively, to eifect breakingof said toggle and hence control of said cooperating contacts.

8. A thermo switch, comprising in combination, a thermostatic stripadapted to flex in response to temperature changes so that it occupies agiven position at normal temperature and flexes from said position'upona change of temperature; a contact secured to said strip; a pivotallymounted member; a contact carried by said pivotally mounted member andin alignment for engagement with the first mentioned contact; andresilient means pivotally supported between the ends of saidthermostatic strip and pivotally mounted member for urging the pivotedmember into either its contact making or breaking position.

9. In a thermo switch, the combination comprising, a support, athermostatic member secured near its mid-portion to said support, acontact secured to said thermostatic member near one end thereof, apivotally mounted member having a cooperating contact mounted thereon,and means pivotally coupling the other end of said thermostatic memberto an end of said pivotally mounted member.

10. In a thermo switch, the combination comprising, a support, athermostatic member secured near its mid-portion to said support, acontact secured to said thermostatic member near one end thereof, apivotally mounted member having ;a cooperating contact mounted thereon,a manual operating member secured to said pivotally mounted member, andmeans pivotally and resiliently coupling the other end of saidthermostatic member to an end of said pivotally mounted member.

prising, a support, a thermostatic member secured near its mid-portionto said support, a contact secured to said thermostatic member near oneend thereof, a pivotally mounted member having a cooperating contactmounted thereon, means pivotally coupling the other end of saidthermostatic member to an end of said pivotally mounted member, andadditional means coupling said pivotally mounted member to said 1thermostatic member so that motion of said thermostatic member in onedirection causes corresponding movement of said pivotally mounted memberand movement of said thermostatic member in the opposite directioncauses said pivotally mounted member to follow after a predeterminedmovement of the thermostatic member.

12. A thermo switch comprising, in combination, a toggle deviceincluding a thermostatic member and acooperating member, saidcooperating member being pivotally mounted; means resiliently forcingsaid members away from each other on one side of the pivotal mounting; acontact mounted on said cooperating member on the other side of thepivotal mounting; a cooperating contact adapted to engage the othercontact; and said thermostatic member changing the direction of theforce of the resilient forcing means so that after a predeterminedchange of direction of the force said contacts disengage with a snapaction.

FREDERICK J. HARDMAN.

